1/*
2 *   Creation Date: <2003/03/14 20:54:13 samuel>
3 *   Time-stamp: <2004/03/20 14:20:59 samuel>
4 *
5 *	<therm_windtunnel.c>
6 *
7 *	The G4 "windtunnel" has a single fan controlled by an
8 *	ADM1030 fan controller and a DS1775 thermostat.
9 *
10 *	The fan controller is equipped with a temperature sensor
11 *	which measures the case temperature. The DS1775 sensor
12 *	measures the CPU temperature. This driver tunes the
13 *	behavior of the fan. It is based upon empirical observations
14 *	of the 'AppleFan' driver under Mac OS X.
15 *
16 *	WARNING: This driver has only been testen on Apple's
17 *	1.25 MHz Dual G4 (March 03). It is tuned for a CPU
18 *	temperatur around 57 C.
19 *
20 *   Copyright (C) 2003, 2004 Samuel Rydh (samuel@ibrium.se)
21 *
22 *   Loosely based upon 'thermostat.c' written by Benjamin Herrenschmidt
23 *
24 *   This program is free software; you can redistribute it and/or
25 *   modify it under the terms of the GNU General Public License
26 *   as published by the Free Software Foundation
27 *
28 */
29
30#include <linux/types.h>
31#include <linux/module.h>
32#include <linux/errno.h>
33#include <linux/kernel.h>
34#include <linux/delay.h>
35#include <linux/sched.h>
36#include <linux/i2c.h>
37#include <linux/slab.h>
38#include <linux/init.h>
39
40#include <asm/prom.h>
41#include <asm/machdep.h>
42#include <asm/io.h>
43#include <asm/system.h>
44#include <asm/sections.h>
45#include <asm/of_platform.h>
46#include <asm/macio.h>
47
48#define LOG_TEMP		0			/* continously log temperature */
49
50#define I2C_DRIVERID_G4FAN	0x9001
51
52static int 			do_probe( struct i2c_adapter *adapter, int addr, int kind);
53
54/* scan 0x48-0x4f (DS1775) and 0x2c-2x2f (ADM1030) */
55static unsigned short		normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
56						 0x4c, 0x4d, 0x4e, 0x4f,
57						 0x2c, 0x2d, 0x2e, 0x2f,
58						 I2C_CLIENT_END };
59
60I2C_CLIENT_INSMOD;
61
62static struct {
63	volatile int		running;
64	struct completion	completion;
65	pid_t			poll_task;
66
67	struct semaphore 	lock;
68	struct of_device	*of_dev;
69
70	struct i2c_client	*thermostat;
71	struct i2c_client	*fan;
72
73	int			overheat_temp;		/* 100% fan at this temp */
74	int			overheat_hyst;
75	int			temp;
76	int			casetemp;
77	int			fan_level;		/* active fan_table setting */
78
79	int			downind;
80	int			upind;
81
82	int			r0, r1, r20, r23, r25;	/* saved register */
83} x;
84
85#define T(x,y)			(((x)<<8) | (y)*0x100/10 )
86
87static struct {
88	int			fan_down_setting;
89	int			temp;
90	int			fan_up_setting;
91} fan_table[] = {
92	{ 11, T(0,0),  11 },	/* min fan */
93	{ 11, T(55,0), 11 },
94	{  6, T(55,3), 11 },
95	{  7, T(56,0), 11 },
96	{  8, T(57,0), 8 },
97	{  7, T(58,3), 7 },
98	{  6, T(58,8), 6 },
99	{  5, T(59,2), 5 },
100	{  4, T(59,6), 4 },
101	{  3, T(59,9), 3 },
102	{  2, T(60,1), 2 },
103	{  1, 0xfffff, 1 }	/* on fire */
104};
105
106static void
107print_temp( const char *s, int temp )
108{
109	printk("%s%d.%d C", s ? s : "", temp>>8, (temp & 255)*10/256 );
110}
111
112static ssize_t
113show_cpu_temperature( struct device *dev, struct device_attribute *attr, char *buf )
114{
115	return sprintf(buf, "%d.%d\n", x.temp>>8, (x.temp & 255)*10/256 );
116}
117
118static ssize_t
119show_case_temperature( struct device *dev, struct device_attribute *attr, char *buf )
120{
121	return sprintf(buf, "%d.%d\n", x.casetemp>>8, (x.casetemp & 255)*10/256 );
122}
123
124static DEVICE_ATTR(cpu_temperature, S_IRUGO, show_cpu_temperature, NULL );
125static DEVICE_ATTR(case_temperature, S_IRUGO, show_case_temperature, NULL );
126
127
128
129/************************************************************************/
130/*	controller thread						*/
131/************************************************************************/
132
133static int
134write_reg( struct i2c_client *cl, int reg, int data, int len )
135{
136	u8 tmp[3];
137
138	if( len < 1 || len > 2 || data < 0 )
139		return -EINVAL;
140
141	tmp[0] = reg;
142	tmp[1] = (len == 1) ? data : (data >> 8);
143	tmp[2] = data;
144	len++;
145
146	if( i2c_master_send(cl, tmp, len) != len )
147		return -ENODEV;
148	return 0;
149}
150
151static int
152read_reg( struct i2c_client *cl, int reg, int len )
153{
154	u8 buf[2];
155
156	if( len != 1 && len != 2 )
157		return -EINVAL;
158	buf[0] = reg;
159	if( i2c_master_send(cl, buf, 1) != 1 )
160		return -ENODEV;
161	if( i2c_master_recv(cl, buf, len) != len )
162		return -ENODEV;
163	return (len == 2)? ((unsigned int)buf[0] << 8) | buf[1] : buf[0];
164}
165
166static void
167tune_fan( int fan_setting )
168{
169	int val = (fan_setting << 3) | 7;
170
171	/* write_reg( x.fan, 0x24, val, 1 ); */
172	write_reg( x.fan, 0x25, val, 1 );
173	write_reg( x.fan, 0x20, 0, 1 );
174	print_temp("CPU-temp: ", x.temp );
175	if( x.casetemp )
176		print_temp(", Case: ", x.casetemp );
177	printk(",  Fan: %d (tuned %+d)\n", 11-fan_setting, x.fan_level-fan_setting );
178
179	x.fan_level = fan_setting;
180}
181
182static void
183poll_temp( void )
184{
185	int temp, i, level, casetemp;
186
187	temp = read_reg( x.thermostat, 0, 2 );
188
189	/* this actually occurs when the computer is loaded */
190	if( temp < 0 )
191		return;
192
193	casetemp = read_reg(x.fan, 0x0b, 1) << 8;
194	casetemp |= (read_reg(x.fan, 0x06, 1) & 0x7) << 5;
195
196	if( LOG_TEMP && x.temp != temp ) {
197		print_temp("CPU-temp: ", temp );
198		print_temp(", Case: ", casetemp );
199		printk(",  Fan: %d\n", 11-x.fan_level );
200	}
201	x.temp = temp;
202	x.casetemp = casetemp;
203
204	level = -1;
205	for( i=0; (temp & 0xffff) > fan_table[i].temp ; i++ )
206		;
207	if( i < x.downind )
208		level = fan_table[i].fan_down_setting;
209	x.downind = i;
210
211	for( i=0; (temp & 0xffff) >= fan_table[i+1].temp ; i++ )
212		;
213	if( x.upind < i )
214		level = fan_table[i].fan_up_setting;
215	x.upind = i;
216
217	if( level >= 0 )
218		tune_fan( level );
219}
220
221
222static void
223setup_hardware( void )
224{
225	int val;
226
227	/* save registers (if we unload the module) */
228	x.r0 = read_reg( x.fan, 0x00, 1 );
229	x.r1 = read_reg( x.fan, 0x01, 1 );
230	x.r20 = read_reg( x.fan, 0x20, 1 );
231	x.r23 = read_reg( x.fan, 0x23, 1 );
232	x.r25 = read_reg( x.fan, 0x25, 1 );
233
234	/* improve measurement resolution (convergence time 1.5s) */
235	if( (val=read_reg(x.thermostat, 1, 1)) >= 0 ) {
236		val |= 0x60;
237		if( write_reg( x.thermostat, 1, val, 1 ) )
238			printk("Failed writing config register\n");
239	}
240	/* disable interrupts and TAC input */
241	write_reg( x.fan, 0x01, 0x01, 1 );
242	/* enable filter */
243	write_reg( x.fan, 0x23, 0x91, 1 );
244	/* remote temp. controls fan */
245	write_reg( x.fan, 0x00, 0x95, 1 );
246
247	/* The thermostat (which besides measureing temperature controls
248	 * has a THERM output which puts the fan on 100%) is usually
249	 * set to kick in at 80 C (chip default). We reduce this a bit
250	 * to be on the safe side (OSX doesn't)...
251	 */
252	if( x.overheat_temp == (80 << 8) ) {
253		x.overheat_temp = 65 << 8;
254		x.overheat_hyst = 60 << 8;
255		write_reg( x.thermostat, 2, x.overheat_hyst, 2 );
256		write_reg( x.thermostat, 3, x.overheat_temp, 2 );
257
258		print_temp("Reducing overheating limit to ", x.overheat_temp );
259		print_temp(" (Hyst: ", x.overheat_hyst );
260		printk(")\n");
261	}
262
263	/* set an initial fan setting */
264	x.downind = 0xffff;
265	x.upind = -1;
266	/* tune_fan( fan_up_table[x.upind].fan_setting ); */
267
268	device_create_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
269	device_create_file( &x.of_dev->dev, &dev_attr_case_temperature );
270}
271
272static void
273restore_regs( void )
274{
275	device_remove_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
276	device_remove_file( &x.of_dev->dev, &dev_attr_case_temperature );
277
278	write_reg( x.fan, 0x01, x.r1, 1 );
279	write_reg( x.fan, 0x20, x.r20, 1 );
280	write_reg( x.fan, 0x23, x.r23, 1 );
281	write_reg( x.fan, 0x25, x.r25, 1 );
282	write_reg( x.fan, 0x00, x.r0, 1 );
283}
284
285static int
286control_loop( void *dummy )
287{
288	daemonize("g4fand");
289
290	down( &x.lock );
291	setup_hardware();
292
293	while( x.running ) {
294		up( &x.lock );
295
296		msleep_interruptible(8000);
297
298		down( &x.lock );
299		poll_temp();
300	}
301
302	restore_regs();
303	up( &x.lock );
304
305	complete_and_exit( &x.completion, 0 );
306}
307
308
309/************************************************************************/
310/*	i2c probing and setup						*/
311/************************************************************************/
312
313static int
314do_attach( struct i2c_adapter *adapter )
315{
316	int ret = 0;
317
318	if( strncmp(adapter->name, "uni-n", 5) )
319		return 0;
320
321	if( !x.running ) {
322		ret = i2c_probe( adapter, &addr_data, &do_probe );
323		if( x.thermostat && x.fan ) {
324			x.running = 1;
325			init_completion( &x.completion );
326			x.poll_task = kernel_thread( control_loop, NULL, SIGCHLD | CLONE_KERNEL );
327		}
328	}
329	return ret;
330}
331
332static int
333do_detach( struct i2c_client *client )
334{
335	int err;
336
337	if( (err=i2c_detach_client(client)) )
338		printk(KERN_ERR "failed to detach thermostat client\n");
339	else {
340		if( x.running ) {
341			x.running = 0;
342			wait_for_completion( &x.completion );
343		}
344		if( client == x.thermostat )
345			x.thermostat = NULL;
346		else if( client == x.fan )
347			x.fan = NULL;
348		else {
349			printk(KERN_ERR "g4fan: bad client\n");
350		}
351		kfree( client );
352	}
353	return err;
354}
355
356static struct i2c_driver g4fan_driver = {
357	.driver = {
358		.name	= "therm_windtunnel",
359	},
360	.id		= I2C_DRIVERID_G4FAN,
361	.attach_adapter = do_attach,
362	.detach_client	= do_detach,
363};
364
365static int
366attach_fan( struct i2c_client *cl )
367{
368	if( x.fan )
369		goto out;
370
371	/* check that this is an ADM1030 */
372	if( read_reg(cl, 0x3d, 1) != 0x30 || read_reg(cl, 0x3e, 1) != 0x41 )
373		goto out;
374	printk("ADM1030 fan controller [@%02x]\n", cl->addr );
375
376	strlcpy( cl->name, "ADM1030 fan controller", sizeof(cl->name) );
377
378	if( !i2c_attach_client(cl) )
379		x.fan = cl;
380 out:
381	if( cl != x.fan )
382		kfree( cl );
383	return 0;
384}
385
386static int
387attach_thermostat( struct i2c_client *cl )
388{
389	int hyst_temp, os_temp, temp;
390
391	if( x.thermostat )
392		goto out;
393
394	if( (temp=read_reg(cl, 0, 2)) < 0 )
395		goto out;
396
397	/* temperature sanity check */
398	if( temp < 0x1600 || temp > 0x3c00 )
399		goto out;
400	hyst_temp = read_reg(cl, 2, 2);
401	os_temp = read_reg(cl, 3, 2);
402	if( hyst_temp < 0 || os_temp < 0 )
403		goto out;
404
405	printk("DS1775 digital thermometer [@%02x]\n", cl->addr );
406	print_temp("Temp: ", temp );
407	print_temp("  Hyst: ", hyst_temp );
408	print_temp("  OS: ", os_temp );
409	printk("\n");
410
411	x.temp = temp;
412	x.overheat_temp = os_temp;
413	x.overheat_hyst = hyst_temp;
414
415	strlcpy( cl->name, "DS1775 thermostat", sizeof(cl->name) );
416
417	if( !i2c_attach_client(cl) )
418		x.thermostat = cl;
419out:
420	if( cl != x.thermostat )
421		kfree( cl );
422	return 0;
423}
424
425static int
426do_probe( struct i2c_adapter *adapter, int addr, int kind )
427{
428	struct i2c_client *cl;
429
430	if( !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA
431				     | I2C_FUNC_SMBUS_WRITE_BYTE) )
432		return 0;
433
434	if( !(cl=kmalloc(sizeof(*cl), GFP_KERNEL)) )
435		return -ENOMEM;
436	memset( cl, 0, sizeof(struct i2c_client) );
437
438	cl->addr = addr;
439	cl->adapter = adapter;
440	cl->driver = &g4fan_driver;
441	cl->flags = 0;
442
443	if( addr < 0x48 )
444		return attach_fan( cl );
445	return attach_thermostat( cl );
446}
447
448
449/************************************************************************/
450/*	initialization / cleanup					*/
451/************************************************************************/
452
453static int
454therm_of_probe( struct of_device *dev, const struct of_device_id *match )
455{
456	return i2c_add_driver( &g4fan_driver );
457}
458
459static int
460therm_of_remove( struct of_device *dev )
461{
462	i2c_del_driver( &g4fan_driver );
463	return 0;
464}
465
466static struct of_device_id therm_of_match[] = {{
467	.name		= "fan",
468	.compatible	= "adm1030"
469    }, {}
470};
471
472static struct of_platform_driver therm_of_driver = {
473	.name		= "temperature",
474	.match_table	= therm_of_match,
475	.probe		= therm_of_probe,
476	.remove		= therm_of_remove,
477};
478
479struct apple_thermal_info {
480	u8		id;			/* implementation ID */
481	u8		fan_count;		/* number of fans */
482	u8		thermostat_count;	/* number of thermostats */
483	u8		unused;
484};
485
486static int __init
487g4fan_init( void )
488{
489	const struct apple_thermal_info *info;
490	struct device_node *np;
491
492	init_MUTEX( &x.lock );
493
494	if( !(np=of_find_node_by_name(NULL, "power-mgt")) )
495		return -ENODEV;
496	info = of_get_property(np, "thermal-info", NULL);
497	of_node_put(np);
498
499	if( !info || !machine_is_compatible("PowerMac3,6") )
500		return -ENODEV;
501
502	if( info->id != 3 ) {
503		printk(KERN_ERR "therm_windtunnel: unsupported thermal design %d\n", info->id );
504		return -ENODEV;
505	}
506	if( !(np=of_find_node_by_name(NULL, "fan")) )
507		return -ENODEV;
508	x.of_dev = of_platform_device_create(np, "temperature", NULL);
509	of_node_put( np );
510
511	if( !x.of_dev ) {
512		printk(KERN_ERR "Can't register fan controller!\n");
513		return -ENODEV;
514	}
515
516	of_register_platform_driver( &therm_of_driver );
517	return 0;
518}
519
520static void __exit
521g4fan_exit( void )
522{
523	of_unregister_platform_driver( &therm_of_driver );
524
525	if( x.of_dev )
526		of_device_unregister( x.of_dev );
527}
528
529module_init(g4fan_init);
530module_exit(g4fan_exit);
531
532MODULE_AUTHOR("Samuel Rydh <samuel@ibrium.se>");
533MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
534MODULE_LICENSE("GPL");
535